Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
Trends Plant Sci. 2011 Feb;16(2):98-107. doi: 10.1016/j.tplants.2010.11.004. Epub 2010 Dec 8.
Galactoglycerolipids are the predominant lipid building blocks of chloroplast membranes and are essential for plant growth. Plant chloroplasts harbor a constitutive set of UDP-Gal-dependent lipid galactosyltransferases that are responsible for the bulk of galactoglycerolipid biosynthesis. A set of paralogs is induced in response to phosphate deprivation, which leads to the remodeling of extraplastidic membranes with a partial replacement of phosphoglycerolipid by digalactosyldiacylglycerol. A third type of galactoglycerolipid biosynthetic enzyme, a UDP-Gal-independent galactoglycerolipid galactosyltransferase, was recently shown to be involved in freezing tolerance. Here, we look at how understanding of the regulation of galactoglycerolipid biosynthesis in chloroplasts by these multiple enzyme sets is rapidly evolving and discuss the increasingly recognized role of lipid remodeling in response to diverse abiotic stresses.
半乳糖甘油酯是叶绿体膜的主要脂质结构单元，对植物的生长至关重要。植物叶绿体中含有一组组成型的依赖 UDP-半乳糖的脂质半乳糖基转移酶，负责半乳糖甘油酯生物合成的大部分。一组同工酶在磷酸盐缺乏时被诱导产生，导致质体外膜发生重塑，磷酸甘油酯部分被二半乳糖基二酰基甘油取代。最近发现，第三种半乳糖甘油酯生物合成酶，即不依赖 UDP-半乳糖的半乳糖甘油酯半乳糖基转移酶，参与了植物的抗冻性。本文探讨了这些多种酶系对半乳糖甘油酯生物合成的调控机制的理解是如何迅速发展的，并讨论了脂质重塑在应对各种非生物胁迫中的作用日益得到认可。
